1. Field of the Invention
This invention relates to diaphragm flush valves, and more particularly to relief valves used in a diaphragm flush valve.
2. Prior Art
Diaphragm flush valves have long been used in water closets and urinals. As the need to conserve water resulting from economic and environmental concerns has increased there has arisen a need to control the amount of water permitted to flow through the water closet or urinal during a single flushing operation. There has also arisen a need to control the rapidity that the flushing operation can be repeated.
These concerns have been addressed through a variety of improvements to the diaphragm flush valve and related vacuum breaker systems used in water closets and urinals. Exemplary of such improvements are the inventions described in U.S. Pat. Nos. 5,026,021, 5,325,547, 6,119,713, 6,189,554, 6,227,219 and 6,554,018.
However, because of the varying water pressures at the inlet side of the diaphragm flush valves and the wide variety of commercially available diaphragm flush valves, the initial calibration and subsequent servicing of these diaphragm flush valves has remained more difficult and time than desired.